The book that helped me greatly in the low point of my life, is The Road Less Travelled by M. Scott Peck. One of my rabbis introduced me to it and had a special session with me reading/learning from it. I slowly but surely turned around my life and am happy looking back at the changes I made.
I learnt what a true friends are, real love, disciplining one-self, and other great concepts that I have for the most part not forgotten even consciously.